Road lighting

ABSTRACT

Systems, devices, and methods are disclosed in which one or more light sources, a detector, a processor and a controller are configured such that light from the one or more light sources improves the ability of a human or automated motor vehicle driver to identify and avoid pedestrians. The one or more light sources may provide spot illumination to moving objects or pedestrians on a road surface, with the spot illumination following the moving object or pedestrians along the portion of the road surface. The one or more light sources may project images on the ground or on other surfaces. The light source may be carried by a pedestrian or on personal transport used by a pedestrian. The light sources may be stationary and provide lighting for a pedestrian street crossing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/991,364 filed on Nov. 21, 2022, which claims priority to U.S.application Ser. No. 17/407,019 filed on Aug. 19, 2021 (now U.S. Pat.No. 11,508,235), which claims priority to U.S. application Ser. No.16/228,516 filed on December 2018 (now U.S. Pat. No. 11,107,346), whichclaims priority to U.S. Provisional Patent Application 62/608,963 filedon Dec. 21, 2017, and to European Patent Application No. 18163162.3filed on Mar. 21, 2018. All of the above-listed applications areincorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The invention relates generally to lighting, and in particular to roadlighting.

BACKGROUND

A human vehicle driver or an automated motor vehicle driver approachingan intersection or other road crossing must identify and avoidpedestrians and cyclists or others on personal transport (allcollectively referred to herein as “pedestrians”) that are in orentering the path of the vehicle. Typically this is facilitated by useof designated cross-walks with built in signaling and illuminationlamps, yet even in these cases in various road and lighting conditions adriver may have difficulty identifying a pedestrian or cyclist in timeto avoid an accident. Additionally, pedestrians and cyclists frequentlycross roadways, or travel along the side of roadways, where no suchapparatus exist.

The definition of a motor vehicle is defined in the U.S. Code of FederalRegulations by CFR 85.1703: (a) For the purpose of determining theapplicability of section 216(2), a vehicle which is self-propelled andcapable of transporting a person or persons or any material or anypermanently or temporarily affixed apparatus shall be deemed a motorvehicle, unless any one or more of the criteria set forth below are met,in which case the vehicle shall be deemed not a motor vehicle: (1) Thevehicle cannot exceed a maximum speed of 25 miles per hour over level,paved surfaces; or (2) The vehicle lacks features customarily associatedwith safe and practical street or highway use, such features including,but not being limited to, a reverse gear (except in the case ofmotorcycles), a differential, or safety features required by stateand/or federal law; or (3) The vehicle exhibits features which renderits use on a street or highway unsafe, impractical, or highly unlikely,such features including, but not being limited to, tracked road contactmeans, an inordinate size, or features ordinarily associated withmilitary combat or tactical vehicles such as armor and/or weaponry. (b)[Reserved] [39 FR 32611, Sep. 10, 1974, as amended at 45 FR 13733, Mar.3, 1980; 73 FR 59178, Oct. 8, 2008; 75 FR 22977, Apr. 30, 2010].

This specification follows this definition of a motor vehicle, so anon-motor vehicle would include such apparatuses or instruments ofconveyance as a unicycle, bicycle, tricycle, scooter, skates, and thelike. This specification designates these non-motor vehicles as personaltransport even though they may transport more than one person, forexample a bicycle or scooter may be capable of accommodating more thanone person. These personal transport may also be self-propelled as longas its maximum speed on a level paved surface is 25 mph or less. Thispersonal transport would include motorized scooters, for example aSegway, or motorized skates.

SUMMARY

This specification discloses systems, devices, and methods in which oneor more light sources, a detector, a processor and a controller areconfigured such that light from the one or more light sources improvesthe ability of a human or automated motor vehicle driver to identify andavoid pedestrians. The one or more light sources may provide spotillumination to moving objects (for example, pedestrians) on a roadsurface, with the spot illumination following the moving object orpedestrians along the portion of the road surface. The one or more lightsources may project images on the ground or on other surfaces. The oneor more light sources may be carried by a pedestrian or on personaltransport used by a pedestrian. The one or more light sources may bestationary and provide lighting for a pedestrian street crossing.

These and other embodiments, features and advantages of the presentinvention will become more apparent to those skilled in the art whentaken with reference to the following more detailed description of theinvention in conjunction with the accompanying drawings that are firstbriefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a plan view of an intersection of tworoads at which is deployed an example embodiment of a road lightingsystem as described herein.

FIG. 2 schematically illustrates a plan view of a pedestrian in a crosswalk using another example embodiment of a road lighting system asdescribed herein.

FIG. 3 schematically illustrates another plan view of an intersection oftwo roads at which is deployed an example embodiment of a road lightingsystem as described herein, with some lighting components shown in sideview rather than plan view.

FIG. 4 schematically illustrates an arrangement of components used in anexample road lighting system as described herein.

FIG. 5 schematically illustrates another plan view of an intersection oftwo roads at which is deployed an example embodiment of a road lightingsystem as described herein, with some lighting components shown in sideview rather than plan view, and with a block diagram superimposedshowing processing and control components of the system.

FIG. 6 is a block diagram of an example embodiment of a road lightingsystem as described herein, showing the system's optionalinterconnection to a mobile device and/or an automobile through anetwork.

FIG. 7 is a block diagram of an example embodiment of a portable roadlighting system as described herein, showing the system's optionalinterconnection to a mobile device and/or an automobile through anetwork.

FIG. 8A and FIG. 8B, respectively, show plan and schematic views of anexample M×N matrix pixelated microLED that may be used in light sourcesin a road lighting system as described herein.

FIG. 9A shows a schematic partial cross-sectional view of a portion ofan example M×N matrix pixelated microLED that may be used in lightsources in a road lighting system as described herein. FIGS. 9B and 9Cshow schematic plan views of example arrangements of n and p electrodesin the example microLED.

FIG. 10A and FIG. 10B each show schematic partial cross-sectional viewsof portions of other example M×N matrix pixelated microLED that may beused in light sources in a road lighting system as described herein.

FIG. 11 shows a schematic partial cross-sectional view of a portion ofanother example M×N matrix pixelated microLED that may be used in lightsources in a road lighting system as described herein.

FIG. 12 shows a schematic partial cross-sectional view of a portion ofanother example M×N matrix pixelated microLED that may be used in lightsources in a road lighting system as described herein, in combinationwith a schematic partial cross-sectional view of a portion of a CMOSsilicon back plane that may be used to switch pixels in the array on andoff.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings, in which identical reference numbers refer to like elementsthroughout the different figures. The drawings, which are notnecessarily to scale, depict selective embodiments and are not intendedto limit the scope of the invention. The detailed descriptionillustrates by way of example, not by way of limitation, the principlesof the invention.

Illumination and/or projection devices (light sources) used in thesystems, devices, and methods described herein may be or comprise an LEDarray or laser system. An LED and laser device is discussed in U.S.patent application Ser. No. 15/802,273 by the same assignee, which ishereby incorporated herein by reference in its entirety. A pixelated LEDarray, including a microLED array and laser pumped array are describedin this reference. Such LED arrays are also described further, below,with reference to FIG. 8A-FIG. 12 .

One of the visual tasks of a motor vehicle driver when approaching acrossing is that a pedestrian is revealed on the road surface bysilhouette vision, the assumption being that the lit road surface allowsa person to be seen in negative contrast as a ‘shadow’. This, however,is an over-simplification of what really occurs. In practice carheadlights provide competing positive contrast, which can at the pointof transition (zero contrast) make a person appear almost invisible. Forthis reason additional local lighting is needed to ensure positivecontrast.

The additional lighting must alert drivers to the presence of thecrossing and make pedestrians as visible as possible on and at thecrossing area. Zones at either end of the crossing, where pedestrianswait to enter, should receive adequate illumination. When measured on avertical plane, the lighting should be significantly higher than thehorizontal illuminance produced by road lighting on the roadway. Itshould also prevent glare from reaching the approaching driver. Onesolution is to use luminaires with asymmetric light output, positioned ashort distance before the crossing in the direction of approachingtraffic, directing the light onto the side of pedestrians facing thedrivers of this traffic.

In addition to designated crosswalks with built in signaling andillumination lamps, there is oftentimes a need for pedestrians to crossroadways where no such apparatus have been built in. Additionally, forpedestrians forced to walk along a roadway where no sidewalks areavailable and for bicycles riding along a roadside without a bicyclelane designation proper illumination is essential at night to avoidcollisions.

New innovations in automotive lighting implementing adaptive lightingusing LED matrix and laser systems may employ a camera that can detectpoorly lit objects such as pedestrians and animals and direct a beam oflight at these objects before the driver would even perceive them.However, until such systems become low enough in cost to be fitted to amajority of vehicles and until such a time when the number of thesevehicles on the road become dominant there is a need to providepedestrian safety to all, no matter what vehicle is driven.

The US Department of Transportation Federal Highway Administrationpublication number FHWA-HRT-08-053 titled “Informational Report onLighting Design for Midblock Crosswalks” contains some basic concepts ofcrosswalk illumination. Illuminance (E) is the amount of light thatfalls on an area of a surface and can be measured in units of lux (lx)and is the same as lumens/m² (1 m/m²). The illuminance on a plane normalto the direction of propagation of light, such as the surface of astreet, is equal to the luminous intensity (I) divided by the square ofthe distance (D). The distance D is the mounting height (h) of the lightsource divided by the sine of the angle between a line from themeasurement point on the horizontal street surface to the light sourceand the vertical:

-   -   E=I/D²=I/(h/ sin Φ)² and for the point on the street directly        beneath the light source) (Φ=90°), then E=I/h².

For a pedestrian walking across the street, the illuminance on thepedestrian is the illuminance E multiplied by the cosine of the anglebetween the direction of propagation of light to the pedestrian andplane normal. This is the vertical illuminance E_(vert) and is theilluminance on a vertical surface, such as a pedestrian. If the heightof the pedestrian is h_(p), then the vertical illuminance on thepedestrian is:E _(vert) =I cos Φ/D ²=(I cos Φ)/((h−h _(p))/ sin Φ)² =I cos Φsin²Φ/(h−h _(p))².

Luminance (L) is the light emitted, transmitted, or reflected from asurface in a specific direction per unit area and can be measured inCd/m² or nit. A candela is the same as a lumen/steradian (lm/sr). In thecase of the pedestrian on the street, an observer in a vehicle wouldperceive the luminance of the (vertical) illuminance reflected off thepedestrian. This is related to how bright the pedestrian appears whenviewed from a specific direction, however the appearance of thesurroundings and the observer's eye adaptation level with the objectluminance also come into play. Luminance and contrast are both used incalculating the appearance of an object or pedestrian in this case.

Light on a surface is either reflected, absorbed, and/or transmitted.For the pedestrian, we are mainly concerned with reflected light. Thereare various types of reflected light such as specular and diffuse.Specular such as a reflection from a mirror or mirror like surface isreflected at an opposite angle of incidence and with an intensity nearlyequal to the incident ray. For a diffuse reflecting surface, light isscattered and reflected in all directions and this is the case for thepedestrian, where clothing is mostly a diffuse reflector. The luminanceof a perfectly diffuse reflector is:L=RE/π,where R is the reflectance, E is the illuminance, and π is pisteradians.

Contrast is the visual difference between an object such as a pedestrianand its background and is often expressed as:C=(L _(p) −L _(background))/L _(background).

Contrast can be positive or negative and can range from very largepositive numbers when the background luminance is very low to somethingclose to −1 when the object luminance is very low.

For the pedestrian in this case,C=((R _(p) E _(vert)/π)−L _(background))/L _(background).

The only variable that can be controlled is the vertical illuminance onthe pedestrian from the crossing light source, lamp, or luminaire. Thebackground luminance is determined by the surroundings and can be verylow in a rural setting or very bright in a city street setting with manywell-lit retail stores. The reflectivity of the pedestrian R_(p) islargely determined by the pedestrians clothing. Choosing white clothingdramatically increases visibility over a wide range of illuminationlevels, whereas denim clothing visibility is greatly impacted byillumination level. Reflective clothing worn at night can dramaticallyimprove the safety of the pedestrian.

Bright road surfaces or bright lighting from shops and stores increasethe background luminance and reduce contrast that make it more difficultto discern pedestrians. To compensate for a higher background luminanceL_(background), vertical illuminance E_(vert) must be increased for adriver to clearly see a pedestrian in the crosswalk. Whether thecontrast of the pedestrian is positive or negative (contrast polarity)and the uniformity of the contrast across the pedestrian (contrastvariance) are two other important issues in determining the visibilityof a pedestrian crossing or walking along a road.

Both contrast polarity and variance will change as a function ofdistance the vehicle driver is from the pedestrian. At distances greaterthan 300 feet, the background luminance is typically higher than that ofthe pedestrian. At distances less than 100 feet, the low beam headlampsof the vehicle provide enough vertical illuminance that the luminance ofthe pedestrian is higher than the background and contrast is positive.At a distance in between 300 and 100 feet, the contrast polarity flipsfrom negative to positive and the pedestrian is not visible during thistransition. Lighting systems must insure that the pedestrian becomesvisible at distances that provide adequate time for the driver torespond and the vehicle to stop.

In actuality, the contrast of a pedestrian is not uniform. The feet andlower legs of a pedestrian may be in negative contrast against a litroad surface and the rest of the pedestrian may be in positive contrastagainst a darker background. With conventional lighting systems it isdifficult to maintain a given level of negative contrast and so isconsidered good practice for a lighting system to provide sufficientpositive contrast to detect pedestrians at a distance long enough for avehicle driver to respond and stop. Depending on background luminance avertical illuminance E_(vert) of at least 10, 20, or 30 lx is needed toprovide adequate pedestrian visibility.

Glare is another consideration in designing a crosswalk illuminationsystem. Glare can be from an opposing vehicle's headlamps approachingbetween the observer and the crosswalk or from a wet road surfacereflecting light towards the observer. Glare happens when luminance ismuch higher than the luminance to which the observer's eyes are adaptedto. Discomfort glare occurs when the observer experiences discomfort orpain when viewing the light source, but disability glare limits orprevents the observer from performing a visual task, such as detecting apedestrian. Road and crosswalk lighting are installed to mitigatedisability glare. Detectors or sensors in the road lighting system cancheck for these glare conditions with on oncoming traffic and roadreflectivity.

An object such as a pedestrian has a threshold contrast C_(Threshold) atwhich the object may just be detected that is a probability of detectionof 50% and depends on such things as visual angle α of the object thatis related to object size, length of observation time t_(observe), theadaption luminance L_(adaption) of the observer, and the age of theobserver. For pedestrian safety, lighting conditions must provide anactual contrast C_(Actual) that is greater than threshold contrastC_(Threshold).

The visibility level VL is defined as the ratio of the actual contrastto the threshold contrast:VL=C _(Actual) /C _(Threshold) =C _(Actual) /C _(Threshold)(α,t_(observe) ,L _(adaption),age)The higher the VL, the greater the chances that the pedestrian is seen.VL provides a measure of the performance of a lighting installation.

FIG. 1 schematically illustrates a plan view of an intersection of tworoads 102 and 103. Embodiments of this invention include light sources100 that can be positioned above (and optionally in front of) acrosswalk 104 for vertical illumination to provide illuminanceE_(horiz), and one or more light sources 105 that can be positioned nearone or both ends of the crosswalk, for example, to provide E_(vert)components and/or light sources to provide more of a horizontalilluminance with E_(vert) and E_(horiz) components. These light sourcesmay also project images as described below. Light sources 100 and 105may be or comprise LED and laser light sources.

Additionally, or alternatively, a light source or light sources can becarried by pedestrian 106 in the form of a handheld device as shown inFIG. 2 . The light source or sources may be for example a mobile phoneor other pocket size device and/or may be worn on the pedestrian, forexample on a belt or clipped on to a pocket, or worn over the shoulder,or around a neck or on bicycle such a on the handlebar, below the seat,on the peddles, wheels or spokes.

The light sources (portable or stationary) can provide E_(vert)illuminance on the pedestrian, and/or project an image 107 such as acrosswalk, stop, yield, or caution sign on the pavement or in a verticallocation noticeable to the driver (but not for example where it woulddazzle or blind a vehicle driver) such as where such a caution, yield,or stop sign may be traditionally placed. Such display images and textmay be projected on both sides of the road where there is traffic fromboth directions. An image 107 presenting the text “stop” may have anoctagonal shape on the road, for example.

Such lighting and projection devices can be used on conventionalcrosswalks where additional lighting and warnings are desired as well aswhere a designated crosswalk is not available but a crossing must bemade. The designated crosswalks may incorporate this technology inmounted devices that also provide E_(vert) and E_(horiz) illumination,can project the crosswalk image, and can project a circle or other shapearound the pedestrian that follows the pedestrian(s) all the way acrossthe street. The projection may also include an arrow indicating thedirection of movement of the pedestrian. A spot light may be usedinstead of or in combination with this lighting that may also follow thepedestrian across the street.

These projections can include images and text on the pavement or abovein locations readily visible to vehicle drivers in all relevantdirections of travel, without dazzle, glare, or blinding and can bemulticolor, such as white, red, yellow, green, and blue (FIG. 2 and FIG.3 ). Such mounted and mobile lighting systems may be used not only forcrossing streets, but by pedestrians and bicycle riders as they walk orride along the edges of street. These devices can also be used onpedestrian or sidewalks that have little or no lighting.

These illumination systems, as shown in FIG. 4 for example, can employone or more detectors, sensors, or cameras that may function in the IR,ultrasonic, radar, and/or LiDAR range. Controllers and processors cantake the detector, sensor, and/or camera output signals as input tooutput lighting control to the light source(s) and control the lightingof pixel elements in the matrix array by controlling which CMOStransistors are turned on and off, or controlling the laser beamrastering of color converting elements or pixels via a MEMS based mirrorarray or an acousto-optic reflector or deflector, for example. The roadlighting system may be activated manually be a pedestrian, for exampleby pushing a button (not shown) on the light source support pole in FIG.4 . The road lighting system may alternatively be activated by apedestrian sending a signal from a mobile device, or may automaticallyactivate upon detecting the presence of a pedestrian.

Also or in addition vehicle to vehicle, infrastructure, pedestrian,target, or object (V2X) communications may be used to provide position,speed, vehicle type and dimensions, etc. to adaptive front, rear, andside exterior lighting systems. GPS communications may additionally beused. Imaging processors can take the input of a camera, IR sensors,LiDAR, radar, ultrasound receivers and such, to map out an image of thetraffic and pedestrian situation that can include location, speed,direction, etc. and send to a controller that can be optionallyintegrated with the processor a signal to control one or more lightingfixtures, light projections of warning images such as traffic type signsthat can be multicolor and include text, as well as crosswalkprojections, and pedestrian highlight, and communications to thevehicles and pedestrians.

For example, a spot light can illuminate a pedestrian and multiple spotlighting providing ample illuminance in the vertical plane E_(vert)(horizontal light on the pedestrian) can be used for each pedestrian inthe crossing that can emanate from a single light source such as anarray or multiple light sources spatially separated can be used. Thespot illumination need not be circular in shape and may be any shapethat illuminates the pedestrian(s) and can follow the pedestrian(s) inreal time. This spot illumination can be provided by light raystraveling in a direction horizontal to the pavement and normal to thevertical plane of the pedestrian and increase the vertical illuminanceE_(vert).

Some extra spot illumination may be provided to the pavement areaE_(horiz) surrounding the pedestrians, enough to get attention of thevehicle driver, but not enough to significantly decrease the pedestriancontrast. The horizontal illuminance can also follow the pedestrian(s)in real time can be any shape including for instance a rectangularsection of the crossing that follows the pedestrian(s) movement. ThisE_(horiz) illuminance can be in the form of a projection, where the areasurrounding the pedestrian can be highlighted with a projection on orabove the pavement, for example a partial or full circular-oval orsquare-rectangular type shape in white and red for example and a greenarrow can be projected indicating the direction of movement.

The horizontal illumination that is not part of the projection can besuppressed in an area around the pedestrian and the projection tomaximize contrast, this suppressed or dark spot of horizontalillumination E_(horiz) can also follow the pedestrian.

Projections of traffic signs images that can include text and color canbe projected on the ground (FIG. 2 and FIG. 3 ) or above or onprelocated mounted screens that can be diffuse reflective or translucentto transmit with some scattering the projection to the opposite sidethat receives the projected image for viewing by the oncoming vehicles.

Instead of or in addition to stationary signs, displays can be used thatcan be programmed to change color and display a warning that istriggered when a pedestrian enters the street, this can be accomplishedwith one of the existing detectors and switched by the lightingcontroller or separate units can be used. The detector can also bedetermine the condition of the roadway, such as reflectivity, from rainand snow for example and adjust the projection accordingly for bettervisibility and location to allow for increased stopping distances. Inaddition or alternately, weather information may be received from aninternet or Ethernet communication. The processor and/or controller maybe connected to a network or the Ethernet that may communicate to theoncoming vehicle a visual and/or audible warning. This can be a visualwarning on a dashboard display, heads-up display (HUD), or simply awarning light. The audible warning can also be from the dash display orHUD or can activate the radio speaker. Alternatively, a mobile phone ornavigation device in the vehicle can be used to sound and/or display awarning. Likewise a warning can be communicated to a pedestrian via amobile phone or other handheld lighting and/or communication device. Thepedestrian's communications device may also be to communicate with thelighting system of the crosswalk to initiate a lighted crossing andreceive instructions from the system on when to enter the crosswalk forexample.

An emissions source such as an infrared (IR) light source, for example aVCSEL or LED array can be used with a detector such as a camera todetect pedestrians. The camera and light source may be mounted in orintegrated with one or more of the visible light sources 100 or 105 asshown in FIG. 4 , for example, or may be mounted separately.

As shown generally in FIG. 5 , signals from the camera (detector) may beprocessed by a processor or image analyzer and used by a lightingcontroller to control light sources 100 and 105 to perform as describedabove. In this figure, the line schematically linking the processor orimage analyzer to light source 105 indicates communication with a camera(detector) co-located with light source 105. Similarly, one of the linesschematically linking the lighting controller to light source 105indicates communication with an emission source used in combination withthe camera (detector) co-located with light source 105.

Optionally, the camera can also detect the higher intensity whiteheadlight beams of an oncoming vehicle as well as the lower intensityred taillights of a passing vehicle. The camera may comprise a CCD anddigital signal processor (DSP) that communicate with each other as shownin FIG. 6 , for example. The DSP may also communicate with the processoror an image analysis unit that can have an image input to which the DSPconnects, an imaging processing unit, a CPU that can send an exposuresignal back to the camera DSP, program, and memory. The camera DSP mayfurther comprise an analog digital converter (ADC) that receives a CCDinput, a color converter unit that outputs a digital image signal to theimage input of the imaging processing unit, an exposure control unitthat outputs a signal to the CCD, a register that receives an exposuresignal from the CPU of the image processing unit and outputs signals tothe exposure control unit and the color converter unit. The CPU of theimage analysis unit or processor can output a signal to a controller ofthe light sources.

Based on the processor output, the controller can turn on and offvarious light sources and control the beam pattern from each of theindividual light sources. Optionally the CPU of the image analysis unitor processor can also output a signal to a control unit of the IR lightsource, or the controller can operate and control all the light sourcesincluding the visible and IR.

This illustrates one embodiment and instead of or in addition to acamera and IR source, ultrasonic, LiDAR, radar, heat sensors that maydetect IR, or pressure sensitive pads that can be installed below groundwith appropriate sensors or detectors may be used along with optionalsupplemental sources used to generate the radiation or signal of thesource to be detected.

As noted above with reference to FIG. 2 , alternatively or in additionto a prelocated and fixedly mounted crosswalk illumination system, aportable system can be used. The illumination system can be carried byor worn on the pedestrian or a bicycle rider on mounted on the bicycleor other means of personal transportation such as skateboard, rollerskates, or scooter. As shown schematically in FIG. 7 , the portabledevice 120 can comprise a projector and/or illuminator, detector,computing module, and a transceiver.

The projector/illuminator can be laser or LED based and use reflectors,lenses, and mirrors. The detector can include one or more sensors todetect motion and/or distance and can be for example a gyroscope, anaccelerometer, GPS receiver, camera, or microphone. The transceiver canconnect to a network or Ethernet and receive and transmit information toa remote server, a mobile device, or vehicle for example. Weather,traffic, and/or road conditions can be transmitted to the portabledevice from the remote server.

Mobile devices such as mobile phones, PDAs or other like devices cantransmit information about vehicles and other pedestrians to theportable device and visa-versa. Information can also be communicateddirectly from vehicles to the portable device of the pedestrian orbicycle rider and information about the pedestrian/bicycle rider can betransmitted back. The computing module can take the detector andtransceiver inputs to generate appropriate illumination and/orprojection display images, text messages, and colors based on theseinputs. The computer module can also send appropriate warnings via thetransceiver to mobile devices, vehicles, and remote servers through thenetwork or Ethernet. This system is particularly useful when streetcrossings are made by pedestrians at non-designated mid-street andintersections and pedestrians or bicycle riders walking or riding alonga dimly lit or busy street.

The controller and processor can be integrated together in the same unitor module. Likewise, visible and IR light source can be integratedtogether in the same fixture or any optional supplemental radiationsource such as ultrasonic, radar, VCSEL, LED array, or LiDAR can beintegrated together in a fixture. It is also possible to integrate allelectronics together in the light source, so that detector radiation,detector, processor, controller as well as visible light emittingelements are together in a module or fixture that may be termed as asmart light or smart lighting source.

As noted above the one or more light sources used in the systemsdescribed herein can provide a horizontal and vertical illuminance. Invarious embodiments the vertical illuminance can be less than thehorizontal illuminance, the vertical illuminance can be equal thehorizontal illuminance, and the vertical illuminance can be greater thanthe horizontal illuminance.

In general, it is desirable that the vertical illuminance be greaterthan the horizontal illuminance, so that the pedestrian is in positivecontrast and background luminance is minimized, although the crosswalkis usually lit, so that its presence is visible. However some variationsof the systems described herein have an optional projection that canwork in conjunction with the spot lighting to provide a line orboundary, partial or full around a pedestrian and/or the projection canbe in the image of a traffic sign or text message. These projections canbe projected on the ground or pavement and can have a local horizontalilluminance that is much higher than the surrounding horizontalilluminance. In these embodiments with projections, the horizontalilluminance of the projection can be higher than the surrounding localhorizontal illuminance and approach the vertical illuminance of thepedestrian, be equal to the vertical illuminance of the pedestrian, orbe greater than the vertical illuminance of the pedestrian.

Preferably, the spatial zone of the projection does not significantlyoverlap with the spatial zone of the vertical illuminance of thepedestrian in the view of drivers of oncoming vehicles and cause alowering of contrast of the pedestrian or the projected image. In oneembodiment. The vertical illuminance is one-half or more the horizontalilluminance. In another embodiment, the vertical illuminance is at leastequal to the horizontal illuminance. In yet another embodiment, thevertical illuminance is at least twice the horizontal illuminance. Inanother embodiment, the vertical illuminance is at least five times thehorizontal illuminance.

In another embodiment, the horizontal illuminance of the projection isat least twice the horizontal illuminance of the surroundings. Inanother embodiment, the horizontal illuminance of the projection is atleast five times the horizontal illuminance of the surroundings. Inanother embodiment, the horizontal illuminance of the projection can beabout equal to the vertical illuminance of the pedestrian. In anotherembodiment, the horizontal illuminance of the projection can be greaterthan the vertical illuminance of the pedestrian. In another embodiment,the vertical illumination of the pedestrian has minimal overlap with thehorizontal illuminance of the projection in oncoming vehicles drivers'view.

In an embodiment, the luminance of a pedestrian is at least twice theluminance of the background or local background (outside of aprojection). In another embodiment, the luminance of a pedestrian is atleast five times the luminance of the background. In yet anotherembodiment, the luminance of a pedestrian is at least ten times theluminance of the background.

In one embodiment, the vertical illuminance of a pedestrian is at least10 lx. In another embodiment, the vertical illuminance of a pedestrianis at least 20 lx. In yet another embodiment, the vertical illuminanceof a pedestrian is at least 30 lx. In still another embodiment, thevertical illuminance of a pedestrian is at least 50 lx. In still yetanother embodiment, the vertical illuminance of a pedestrian is at least100 lx.

The systems described herein may provide spot lighting or illuminationof the pedestrian, where the vertical illumination of an object orpedestrian can be greater than the vertical illumination outside thespatial zone of this spot illumination. In an embodiment, the spotvertical illumination is at least 1.5 times the vertical illuminationoutside the spot. In another embodiment, the spot vertical illuminationis at least twice the vertical illumination outside the spot. In yetanother embodiment, the spot vertical illumination is at least fivetimes the vertical illumination outside the spot. The horizontalillumination can also be dimmed or turned off around the pedestrian andthis dark hole follow the pedestrian, so that the vertical illuminationof the spot lighting and horizontal illumination of the optionalprojection can be viewed with increased contrast to a vehicle driver.

The power consumption for the road lighting systems described herein canbe lower than conventional systems. For example, the spot lighting ofindividual pedestrians in a crossing can supply excellent verticalilluminance on the pedestrian for the entire length of the crossing,without having to supply this level and uniformity of verticalillumination throughout the entire length of the crossing because thespot follows the pedestrian(s).

In contrast, for conventional lighting systems, the power consumptiondoes depend on the area of illumination. For a typical crosswalk 4 mwide with a conventional lighting system luminaire mounted 4 m ahead ofoncoming traffic from the center of the crosswalk and 0.5 m away fromthe curb at a height of 5 m: 150 W may be consumed for a single lanestreet 3.5 m long with a 13500 lm metal halide bulb, can have a verticalillumination average of 85 lx with a poor uniformity of 0.6 and 500 Wmay be consumed for a two lane street 7 m long using two 19000 lm bulbs,can have a vertical illumination average of 180 lx with a uniformity of0.7.

The stationary lighting systems described herein can be turned off whenpedestrians are not detected or can be dimly lit with a horizontalilluminance to make drivers aware of the crossing even thoughpedestrians are not present. When a pedestrian is detected, thehorizontal illumination can increase, so that the crosswalk issufficiently illuminated and increased vertical illumination is providedto make the pedestrian readily visible. The inventive crosswalk lightingsystem may use less than 300 W for a two lane crossing and less than 90W for a single lane crossing. Furthermore, such a system may use lessthan 200 W for a two lane crossing and less than 60 W for a single lanecrossing. For a portable lighting system of this invention powerconsumption may be less and may be less dependent on the length of thecrossing since vertical illumination is provided from the portabledevice at a nearly fixed distance to the holder and if projections arealso used, they can be of a fixed length for example 4 to 10 ft. longprojections of a crosswalk.

Older designs for crosswalk lighting placed the Luminaires directly overthe crosswalk. This provides high pavement illuminance E_(horiz), butmay not adequately light the pedestrian. Newer designs move the lightsource at least 2 m before the cross walk relative to the direction ofoncoming traffic to provide the necessary vertical illuminance(E_(vert)) of the pedestrian. For computer modeling a pedestrian may berepresented as a cylinder 5 feet 10 inches tall, 1 foot in diameter witha reflectance of 18%. Refitting or retrofitting the older designs thattypically use high pressure sodium or metal halide lamps with a LEDarray and/or laser light sources described herein may provide greatlyimproved pedestrian visibility without having to relocate theinfrastructure. The use of these lighting systems using LED arraysand/or laser light source, detector, optional emission for the detector,processor and controller may provide for greatly improved pedestrianlighting and safety and may save on power consumption. Improved safetyand energy consumption is possible whether the installation is of a newdesign specifically for employing this technology, a retrofit of new orold convention design, or a portable system.

As noted above, the illumination and/or projection devices used in thesystems, devices, and methods described herein may be or include an LEDarray or laser. Some aspects of such LED arrays are further describednext, with reference to FIG. 8A-FIG. 12 .

FIGS. 8A and 8B show plan and schematic views of an example M×N matrixpixelated microLED 200, comprising M×N pixels 205. The number ofindividual pixels in the array can be, for example, 2 to 10 and can beused in a mobile phone flash and the like, 10 to 50 in some embodiments,50 to 100 in some embodiments, 100 to 500 in other embodiments, 500 to1000 in other embodiments, 1000 to 2500 in yet other embodiments, 2500to 5000 in yet other embodiments, 5000 to 10000 in still yet otherembodiments, these can be used for instance in adaptive vehicleheadlights, adaptive street lights, adaptive crosswalk illumination andthe like. Still other embodiments include 10000 to 100000 and 100000 to500000 that can use LED or laser light sources, 500000 to 1000000, and1000000 to 100000000 that can use laser light source or sources such asa raster scanned laser(s) may be used. Raster scanning may beaccomplished with a microelectromechanical system (MEMS) based mirror orwith an acousto-optic reflector or deflector. These embodiments can besuitable for displays.

FIG. 9A shows a partial cross sectional view of one embodiment of an LEDmatrix array 200. The n (205) and p-type (210) semiconductor layerssandwich an active region that emits light. The n and p-typesemiconductor layers and the active region may themselves containmultiple layers of different doping levels and compositions. For examplethe active region may be a single light emitting layer, a homojunction,a single heterojunction, a double heterojunction or heterostructure, asingle quantum well heterostructure (SQW), a multiple quantum well (MQW)structure, or a superlattice (SL) structure. The n and p-typesemiconductor layers may be for example GaN or AlGaN and the activeregion may be InGaN and GaN. Other semiconductor material systemsinclude AlGaInP, AlGaAs, and AlGaInAsP for example. Once the epitaxiallayers are grown, trenches can be etched through the p-layers and intothe thicker n-layer.

The p-n junction can be passivated with a dielectric, such as SiO_(x),AlO_(x), SiON, SiAlON, TaO_(x), AlO_(x), or Si₃N₄ or the like to preventshorting or may be isolated by ion implantation, such as hydrogen,carbon, and oxygen ions for example. In the example of FIG. 9A, suchdielectric may be deposited on surfaces of the n and p layers in regions220. Metal contacting the n-layer and the dielectric can extend to thep-layer side. P-metal may be deposited before or after the trench etch.

In one embodiment, metal contacts 240 to n-type material can extend tothe p-side surface with isolation from the p-type material. The p-typeand n-type metal electrodes may then be on the same side and can bebonded to a silicon wafer that may contain electronics such as aswitching transistor, TVS, open and/or short detection and the like.Bonding can include soldering, such as AuSn or SnAgCu (SAC) solders, ora GGI bond using thermal and ultrasonic energy to form an Au bondinterconnect.

The metal may be extended by plating for example past the n-layer afterthe growth substrate, for example sapphire, is removed. The n-metal canserve as the seed for plating and may be exposed by growth substrateremoval, if the p-side trench and metallization extends completelythrough the n-layer to the substrate, by thinning the n-layer, or asubsequent trench etch from the n-side after substrate removal. The pand n-metal contacts are preferably reflective and may be for exampleAg, Al, Ni, Ti, TiW, TiWN, Au, Zn and combinations and layers thereof.The extensions beyond the n-surface can be a reflective metal asdescribed above or a TCO, such as ITO, ISO, AZO, IZO or a dielectric,such as sapphire, photoresist, SiO_(x), SiON, SiAlON, TaO_(x), AlO_(x),or Si₃N₄ that may be reflective by TIR or a metallic coating.

The extensions may be used to hold or contain a wavelength converter225, such as phosphor in silicone or other suitable binder or a ceramicphosphor. Phosphor may be applied by dispensing, ink-like jet printing,sedimentation, EPD, stenciling, spraying or molding. The pixel may befor example square, round, oval, or rectangular in shape. FIG. 9B andFIG. 9C show that the p-electrode 230 can be square, rectangular,circular, or oval in shape surrounded by a thin dielectric 235 and then-electrode 240 around the perimeter. The n-electrode may completelysurround (FIG. 9A and FIG. 11 ), partially surround (FIG. 10A), or be toone side of the p-electrode (FIG. 12 ). The n-electrode may also overlapthe p-electrode separated by a dielectric (FIG. 10B).

The electrodes may be connected in the device or by the Si backplane 245(schematically shown for example in FIG. 12 ) in a common cathode oranode configuration. The n and p-layer and electrode positions are shownin the figures for convenience, but their positions can also be swappedthat is opposite from what is shown.

Multiple matrix arrays may be used in an illumination device and thesemultiple arrays may be spaced apart from one another and do not have tobe adjacent in an extended matrix configuration. For instance, onematrix in a crosswalk illumination system may provide for crosswalkillumination and another matrix is used to provide spot lighting thatfollows the pedestrians as they cross the street.

Pixel size d1 (FIG. 9A and FIG. 11 ) may be for example from submicronto 1 micron, 1 micron to 10 microns, 10 microns to 50 microns, and 50microns to 500 microns in various embodiments. Pixel spacing d2 may bedetermined by width of the metal layer (FIG. 11 ) or may include anactual gap (FIG. 9A). Pixel spacing d2 may be for example less than 0.1micron, 0.1 to 1 micron, 1 micron to 5 microns, and 5 to 50 micronsembodiments. Pixel spacing d2 may depend on pixel size d1.

Pixels may be in any shape or combination of shapes, for examplecircular, square, rectangular, triangular, hexagonal and combinationsthereof. Phosphor particle sizes may depend on pixel size d1 and may beat least d1/10 or smaller in size. The luminous flux of these arrays canbe 10-4 to 10-3 lumens (lm), 10-3 to 0.1 lm, 0.1 to 10 lm, 10 to 1000lm, 1000 to 10000 lm, 10000 to 100000 lm, and 0.1 to 5×10⁶ lm in someembodiments. The luminance of these arrays can be 10 to 100 lux (lx),100 to 500 lx, 500 to 1000 lx, 1000 to 50000 lx, 50000 to 500000 lx,0.5×10⁶ to 1×10⁶ lx, 1×10⁶ to 10×10⁶ lx, and 10×10⁶ to 5000×10⁶ lx insome embodiments. The illuminance of these arrays may be 10 to 100 nit,100 to 1000 nit, 1000 to 10000 nit, 10000 to 100000 nit, 0.1×10⁶ to1×10⁶ nit, 1×10⁶ to 1000×10⁶ nit in some embodiments. The luminance andilluminance of these arrays can be measured without external optics andcan include laser as well as LED arrays. Luminous efficacy can be 1 to20 lm/W, 20 to 200 lm/W, and 200 to 500 lm/W in some embodiments. Thesearrays may be packaged with primary optics, such as lenslet arrays orcompound parabolic concentrators (CPC) and may include secondary opticssuch as a projection lens.

This disclosure is illustrative and not limiting. Further modificationswill be apparent to one skilled in the art in light of this disclosureand are intended to fall within the scope of the appended claims.

The following enumerated paragraphs (clauses) provide additionalnon-limiting examples of the disclosure.

-   -   1. A lighting system comprising: a light source; a detector; a        processor; and a controller; wherein the system is configured so        that light from the light source illuminates a portion of road        surface and provides spot illumination to moving objects on the        road surface, such that the spot illumination follows the moving        object along the portion of the road surface.    -   2. The lighting system of clause 1, wherein the lighting system        is stationary and provides lighting for a pedestrian street        crossing.    -   3. The lighting system of clause 1, wherein the lighting system        is portable and provides lighting for one of a pedestrian and a        pedestrian using personal transport.    -   4. The lighting system of clause 3, wherein the personal        transport is one of bicycle, scooter, Segway and skates.    -   5. The lighting system of clause 1, wherein the light source        comprises one of a LED and laser.    -   6. The lighting system of clause 1, wherein the light source        comprises a LED array.    -   7. The lighting system of clause 1, wherein the light source        comprises a microLED array.    -   8. The lighting system of clause 1, wherein the light source        comprises a laser and wavelength converter.    -   9. The lighting system of clause 1, wherein the system is        further configured to provide a spot of reduced horizontal        illuminance that follows the moving object along the portion of        the road surface for increased contrast.    -   10. The lighting system of clause 1, wherein the system further        comprises a projection at least partially surrounding and        following a pedestrian.    -   11. The lighting system of clause 10, wherein the projection is        one of circular, oval, square, and rectangular.    -   12. The lighting system of clause 11, wherein the projection        further comprises an arrow that indicates the direction of the        pedestrian.    -   13. The lighting system of clause 1, wherein the system further        comprises a projection of one of a traffic sign and text message        visible to a vehicle driver.    -   14. The lighting system of clause 1, wherein the system further        provides a projection that comprises one or more color.    -   15. The lighting system of clause 7, wherein the microLED array        comprises LED chips, mounted and electrically connected to CMOS        circuitry on a silicon wafer, wherein the LED chips are        separated by a dielectric and metal that extends above a        semiconductor surface of the LED chip and is filled with a        wavelength converter.    -   16. The lighting system of clause 1, wherein the system        comprises a vertical illuminance that is at least twice the        horizontal illuminance.    -   17. The lighting system of clause 1, wherein the system        comprises a vertical illuminance that is at least five times the        horizontal illuminance.    -   18. The lighting system of clause 10, wherein the horizontal        illuminance of the projection is at least twice the horizontal        illuminance of the surrounding pavement.    -   19. The lighting system of clause 10, wherein the horizontal        illuminance of the projection is at least equal to the vertical        illuminance of the pedestrian.    -   20. The lighting system of clause 10, wherein the horizontal        illuminance of the projection is less than the vertical        illuminance of the pedestrian.    -   21. The lighting system of clause 1, wherein the system further        comprises a transceiver capable of communication with a network.    -   22. The lighting system of clause 21, wherein the system further        comprises a transceiver capable of communication with at least        one of a vehicle, a mobile phone, and a remote server over the        network.    -   23. The lighting system of clause 1, wherein the lighting system        comprises a non-motor vehicle lighting system.    -   24. A portable illumination device comprising: a light source; a        detector; a computer; and a transceiver; wherein, the light        illuminates a holder and projects an image on the ground.    -   25. The portable illumination device of clause 24, wherein the        light source comprises one of a LED and laser.    -   26. The portable illumination device of clause 24, wherein the        detector is one of an accelerometer, gyroscope, and GPS.    -   27. The portable illumination device of clause 24, wherein the        transceiver can communicate with at least one of a vehicle, a        mobile phone, and a remote server over a network.    -   28. The portable illumination device of clause 24, wherein the        image at least partially surrounds and follows the holder.    -   29. The portable illumination device of clause 24, wherein the        image further comprises an arrow that indicates the direction of        the holder.    -   30. The portable illumination device of clause 24, wherein the        image comprises one of a traffic sign and text message visible        to a vehicle driver.    -   31. The portable illumination device of clause 24, wherein the        image comprises one or more color.    -   32 The portable illumination device of clause 24, wherein the        holder is one of a pedestrian and a pedestrian on a personal        transport.    -   33 The portable illumination device of clause 32, wherein the        personal transport is one of a bicycle, scooter, Segway and        skates.    -   34. The portable illumination device of clause 24, wherein the        holder is one of a bicycle, scooter, Segway and skate.    -   35. The portable illumination device of clause 24, wherein the        holder comprises a non-motor vehicle.

What is claimed is:
 1. A portable illumination device comprising: amicroLED array comprising: a plurality of pixels arranged in a matrix,each of the pixels being 500 microns or less in size, a spacing betweenadjacent pixels being 50 microns or less; and a CMOS back plane arrangedto switch individual ones of the pixels on and off; at least one of atransceiver and a detector; and a processor configured to receivesignals and process signals from the detector, from the transceiver, orfrom the detector and the transceiver; and a controller configured toreceive signals from the processor and in response operate the microLEDarray to provide spot illumination directed at the holder of theillumination device comprising a spot of reduced horizontal illuminancein a plane parallel to the roadway that provides increased visualcontrast on the holder.
 2. The portable illumination device of claim 1,wherein the microLED array is configured to have a luminance from 10 to100 lux.
 3. The portable illumination device of claim 1, wherein theportable illumination device comprises the detector, the detector beingconfigured to detect an object or person on or near a roadway.
 4. Theportable illumination device of claim 3, wherein the portableillumination device comprises the transceiver, the signals received bythe controller relate to the object or person on or near the roadwaydetected by the detector, and the controller is configured to send viathe transceiver information and/or warnings about the holder through anetwork to devices or vehicles in proximity with the object or person.5. The portable illumination device of claim 1, wherein the plurality ofpixels comprise a matrix of 10 to 500 pixels.
 6. The portableillumination device of claim 1, wherein the portable illumination deviceis a mobile phone and the microLED array is a mobile phone flash.
 7. Aportable illumination device comprising: a microLED array comprising: aplurality of pixels arranged in a matrix, each of the pixels each of thepixels being 500 microns or less in size, a spacing between adjacentpixels being 50 microns or less; and a CMOS back plane arranged toswitch individual ones of the pixels on and off; at least one of atransceiver and a detector; and a processor configured to receivesignals and process signals from the detector, from the transceiver, orfrom the detector and the transceiver; a controller configured toreceive signals from the processor and in response operate the microLEDarray to provide spot illumination directed at the holder of theillumination device and to project an image on the ground providinginformation relating to the holder of the illumination device.
 8. Theportable illumination device of claim 7, wherein the microLED array isconfigured to have a luminance from 10 to 100 lux.
 9. The portableillumination device of claim 7, wherein the portable illumination devicecomprises the detector, the detector being configured to detect anobject or person on or near a roadway.
 10. The portable illuminationdevice of claim 9, wherein the portable illumination device comprisesthe transceiver, the signals received by the controller relate to theobject or person on or near the roadway detected by the detector, andthe controller is configured to send via the transceiver informationand/or warnings about the holder through a network to devices orvehicles in proximity with the object or person.
 11. The portableillumination device of claim 7, wherein the plurality of pixels comprisea matrix of 10 to 500 pixels.
 12. The portable illumination device ofclaim 7, wherein the portable illumination device is a mobile phone andthe microLED array is a mobile phone flash.
 13. A road lighting sourcecomprising: a microLED array configured to have a luminance of 10 to 100lux (lx) and comprising: a plurality of pixels arranged in a matrix,each of the pixels comprising an n-type semiconductor layer, a p-typesemiconductor layer, and an active region between the n-typesemiconductor layer and p-type semiconductor layer, each of the pixelsbeing 500 microns or less in size, a spacing between adjacent pixelsbeing 50 microns or less; a plurality of metal contacts disposed indirect contact with sidewalls of the n-type semiconductor layer andsurrounding the p-type semiconductor layer; and a CMOS back planearranged to switch individual ones of the pixels on and off.
 14. Theroad lighting source of claim 13, wherein the metal contacts extend pastthe sidewalls of the n-type semiconductor layer away from the p-typesemiconductor layer.
 15. The road lighting source of claim 13 whereinthe p-type semiconductor layer is surrounded by trenches formed bysidewalls of the p-type semiconductor layer and sidewalls of the metalcontacts.
 16. The road lighting source of claim 14, further comprising aphosphor material disposed on each of the pixels, wherein the metalcontacts form trenches above the n-type semiconductor layer within whichthe phosphor material is disposed, such that the phosphor material is indirect contact with the metal contacts and the n-type semiconductorlayer.
 17. The road lighting source of claim 16, wherein the metalcontacts are in direct contact with respective n-type semiconductorlayers of adjacent pixels.
 18. The road lighting source of claim 15,wherein the trenches are filled with dielectric material.
 19. The roadlighting source of claim 18, wherein the dielectric material is at leastone of SiO_(x), AlO_(x), SiON, SiAlON, TaO_(x), AlO_(x).
 20. The roadlighting source of claim 18, wherein the dielectric material iscompletely surrounded by the metal contacts.